The present invention relates to a plasma addressed liquid crystal display. Common displays include a phosphor display tube using a low-speed electron beam, a plasma display using gas discharge, an electro-luminescence (EL) display using the electro-luminescence effect, an electro-optical liquid crystal display (LCD), as well as a traditional cathode ray tube using a high-speed electron beam. The various displays are selectively adapted according to their characteristics since they have different functions and structures. Their common purpose is to visualize an electrical image signal or a data signal.
Recently, a matrix-type display compositely constructed with the plasma discharge device and electro-optical device, which is one type of LCD, was disclosed in U.S. Pat. No. 4,896,149 by Tektronix. This display addresses lines by linear plasma discharge which is shown in FIG. 1. Referring more particularly to FIG. 1, the display is constructed such that a liquid crystal shutter 10 in which a plurality of striped data electrodes 14 are arranged in parallel, overlaps a plasma addressing unit 20 in which a plurality of unit scan lines 21 are arranged at right angles to striped data electrodes 14 of liquid crystal shutter 10.
With reference to FIG. 2, liquid crystal shutter 10 has first and second transparent substrates 12 and 13 between which liquid crystal 16 is filled. Striped data electrodes 14 are formed on the inner side of the first substrate 12. Addressing unit 20 has a plurality of grooves 24 which form scan lines 21 on a third substrate 25 at right angles to the striped pixels. A pair of electrodes 22 and 23 are provided on either side of the bottom of each groove 24. In this configuration, third substrate 25 is adhesively fixed to bottom substrate 13 of liquid crystal shutter 10 so that grooves 24 form a closed discharge space in which discharge gas is filled.
In liquid crystal shutter 10, since a data signal is applied to a selected data electrode 14, a potential for activating the liquid crystal is formed along a selected data electrode 14. In plasma addressing u31it 20, according to the ionized state of each discharge line due to the plasma discharge of each sequentially-selected plasma scanning line 21, a positive potential for activating the liquid crystal 16 is formed linearly along scanning line 21 on second substrate 13 in contact with the liquid crystal. Accordingly, a potential difference is formed by a selected data electrode 14 of liquid crystal shutter 10 and scanning line 21 of plasma addressing unit 20. Liquid crystal positioned at the intersection is activated and oriented by the potential difference at the interconnection, which forms a light passing area through which light from the rear ward back light generator passes.
In other words, in plasma addressing unit 20, when voltage of a predetermined potential is applied to a pair of parallel electrodes 22 and 23 on a sequentially selected scanning line, linear direct-current-discharge occurs between parallel electrodes 2 and 23. Due to this, a linear ionization region is formed along scanning line 21 on the thinner second substrate 13. When the linear ionization region is formed on second substrate 13 by the linear discharge on scanning line 21 selected by the scanning signal, a data signal is selectively applied to data electrode 14 of the upper liquid crystal shutter 10. When liquid crystal is then activated by the potential difference at the intersection of the selected data electrode 14 and the selected and discharged scanning line 21 and is locally re-arranged, back light passes, forming one picture point.
The above display is a unique flat-panel display in which the liquid crystal orientates itself by means of the pixel electrodes and discharge lines. Its drawback is that as described above, since the addressing unit requires, as its structural base, grooves 24 formed on third substrate 25 and a pair of electrodes 22 and 23 formed on the bottom thereof, the manufacture of the display is very elaborate. In other words, to form groove 24 on third substrate 25, a complicated etching process is required. Especially, forming a pair of electrodes on the bottom of the groove requires more than a simple silk screen printing method, i.e., a photolithography method including a metal deposition. Such a technique for forming a groove on glass and forming an electrode thereon is very complicated, especially for a large-screen display.